Simulation of flow in porous media, such as hydrocarbon producing formations in the earth, generally involves the subdividing of the porous media into smaller portions or blocks using some form of gridding. The most popular forms for solving the equations for flow in porous media for this subdividing of the domain (gridding) are finite differences, finite volumes, and finite elements. Regardless of the form of solution, it is generally observed that finer grids (or smaller blocks) produce more accurate answers from a numerical error estimation point of view. Generally, however, finer grids require greater computing times to produce an answer. Parallel computing has helped to reduce the computing elapsed times to some extent; however, to capture as many scenarios or to better quantify uncertainties in the physical properties of the porous medium requires many simulations. Often, the models are reduced in size to reduce the time required to run each simulation. Reducing the size of the model often involves “coarsening” or “upscaling” the model. Coarsening the model while approximately maintaining the properties of the fine grid so that the coarser or “upscaled” models are able to approximately reproduce the physics in the finely gridded models, without simply interpolating the results of the fine models, is a challenge.